The nominal iput voltage to the powersupply to the WRT54G V1.1 is 120 volts. You can get adapters for the plugs on the powersupply for European outlets. European electrical system work at 50 htz not the 60 htz in the US. The powersupply and thr router will work at voltages around 120 volts, since the voltage on American power systems vary during the day. Actual 120 volts is not realy 120 volts, but the rms voltage.